package ar.edu.sccs.util;

import java.io.IOException;
import java.io.StringWriter;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.DocumentResult;
import org.dom4j.io.DocumentSource;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;


/**
 * Utilities to parse strings into XML DOM Documents and vice versa
 */
public final class XmlHelper {
    
    /**
     * uses Dom4j to neatly format a given XML string
     * by adding indents, newlines etc.
     */
    public static String getAsPrettyXml(String xmlString) {
        return getAsPrettyXml(parse(xmlString));
    }
    
    /**
     * Override that accepts an XML DOM Document
     * @param document XML as DOM Document
     */
    public static String getAsPrettyXml(Document document) {
        OutputFormat format = new OutputFormat(" ", true);
        format.setSuppressDeclaration(true);
        StringWriter out = new StringWriter();
        XMLWriter writer = new XMLWriter(out, format);
        try {
            try {
                writer.write(document);
            } finally {
                writer.close();
            }
        } catch (IOException ioe) {
            throw new RuntimeException(ioe);
        }
        return out.toString().trim();
    }
    
    /**
     * Converts a String into XML by parsing into a DOM Document
     * uses Dom4j
     */
    public static Document parse(String xmlString) {
        try {
            return DocumentHelper.parseText(xmlString);
        } catch (DocumentException de) {
            throw new RuntimeException(de);
        }
    }
    
    public static Element getNewElement(String name) {
        return DocumentHelper.createElement(name);
    }
    
    public static Document getNewDocument(String rootElementName) {
        Document d = DocumentHelper.createDocument();
        d.addElement(rootElementName);
        return d;
    }
    
    public static Document transform(Document source, Document stylesheet) {
        TransformerFactory factory = TransformerFactory.newInstance();
        try {
            Transformer transformer = factory.newTransformer(new DocumentSource(stylesheet));
            DocumentResult result = new DocumentResult();
            transformer.transform(new DocumentSource(source), result);
            return result.getDocument();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}
